Printing device and printing method

Abstract

A solder paste printer for which a pressing force of squeegee towards a stencil when spreading solder paste is smaller than a printing pressure when performing solder paste printing. The force with which the solder paste is pressed downwards by the squeegee is weak, and instead of solder paste being pressed down, it spreads along the squeegee. Also, the moving speed of the squeegee when spreading the solder paste is faster than the moving speed of the squeegee when printing solder paste. Thus, because the squeegee is moving fast, before the solder paste is pressed down sufficiently to be printed, the solder paste spreads out along the squeegee. Accordingly, it is possible to appropriately spread the solder paste along the direction in which the squeegee extends.

The invention claimed is: 
     
       1. A printing device comprising:
 a stencil; 
 a squeegee configured to slide on an upper surface of the stencil in which through-holes are formed; 
 a moving device configured to move the squeegee back and forth along a first direction, the moving device including a pair of guide rails extending in the first direction, and a slider slidably attached to the pair of guide rails; 
 a squeegee raising and lowering device which raises and lowers the squeegee, the squeegee raising and lowering device including a holding tool and a motor; and 
 a control device configured to control operation of the moving device, the control device including
 a spreading section configured to spread a viscous material loaded on the upper surface of the stencil so as to form a roll of the viscous material disposed in front of the squeegee in the first direction and extending in a second direction in which the squeegee extends by controlling the moving device to slide the squeegee, the second direction being perpendicular to the first direction, and a thin layer of the viscous material disposed to a rear of the squeegee in the first direction, a length of the thin layer of the viscous material in the second direction being equal to a length of the roll of the viscous material in the second direction at a front end of the thin layer of viscous material in the first direction, and the length of the thin layer of the viscous material in the second direction being less than the length of the roll of the viscous material in the second direction at a rear end of the thin layer of viscous material in the first direction, and 
 a printing section configured to squeeze the roll of the viscous material that was spread by the spreading section into the through-holes of the stencil by controlling the moving device to slide the squeegee such that the viscous material is printed onto a board that is closely contacting a lower surface of the stencil, 
 
 wherein the control device is configured to control the squeegee raising and lowering device so that a pressing force of the squeegee towards the stencil when the squeegee is slid by the spreading section is smaller than a pressing force of the squeegee towards the stencil when the squeegee is slid by the printing section. 
 
     
     
       2. The printing device according to  claim 1 , wherein
 the control device is configured to control the squeegee raising and lowering device so that the pressing force of the squeegee towards the stencil when the squeegee is slid by the spreading section is larger at a sliding end period than at a sliding beginning period. 
 
     
     
       3. The printing device according to  claim 1 , wherein the spreading section is configured to control the moving device to slide the squeegee back and forth 1.5 times in the first direction to form the roll of the viscous material. 
     
     
       4. A printing device comprising:
 a stencil; 
 a squeegee configured to slide on an upper surface of the stencil in which through-holes are formed; 
 a moving device configured to move the squeegee back and forth along a first direction, the moving device including a pair of guide rails extending in the first direction, and a slider slidably attached to the pair of guide rails; and 
 a control device configured to control operation of the moving device, the control device including
 a spreading section configured to spread a viscous material loaded on the upper surface of the stencil so as to form a roll of the viscous material disposed in front of the squeegee in the first direction and extending in a second direction in which the squeegee extends by controlling the moving device to slide the squeegee, the second direction being perpendicular to the first direction, and a thin layer of the viscous material disposed to a rear of the squeegee in the first direction, a length of the thin layer of the viscous material in the second direction being equal to a length of the roll of the viscous material in the second direction at a front end of the thin layer of viscous material in the first direction, and the length of the thin layer of the viscous material in the second direction being less than the length of the roll of the viscous material in the second direction at a rear end of the thin layer of viscous material in the first direction, and 
 a printing section configured to squeeze the roll of the viscous material that was spread by the extending section into the through-holes of the stencil by controlling the moving device to slide the squeegee such that the viscous material is printed onto a board that is closely contacting a lower surface of the stencil, 
 
 wherein the control device is configured to control the moving device so that a moving speed of the squeegee when the squeegee is slid by the spreading section is greater than a moving speed of the squeegee when the squeegee is slid by the printing section. 
 
     
     
       5. The printing device according to  claim 4 , wherein
 the control device is configured to control the moving device so that the moving speed of the squeegee when the squeegee is slid by the spreading section is greater at a sliding beginning period than at a sliding end period. 
 
     
     
       6. The printing device according to  claim 4 , wherein the spreading section is configured to control the moving device to slide the squeegee back and forth 1.5 times in the first direction to form the roll of viscous material.